(6d) Assessing the Fidelity of Additively Manufactured Objects

Despite the rapid growth of additive manufacturing (AM), its broad implementation is still hindered by challenges including limited material options, inconsistent part quality, and fabrication defects. Although current additive manufacturing technologies use high-precision machines, in practice, manufactured parts can deviate significantly in both shape and structure. Thus, characterization of the fidelity of manufactured objects is critical to establish and ensure performance. Although there are many ways to compare printed objects and the digital counterparts from which they are created, many of these methods are biased due to the way that measurements are made or the subjectivity of alignment procedures. To remove these subjectivities and biases, alternative printability metrics were developed based on a new alignment technique. Rather than using subjectively selected landmarks, the new method uses the axis of the minimum moment of inertia as reference. A boundary-based printability index (PI_B) and a volume-based printability index (PI_v) were then used to assess external dimensions and object volume. X-ray computed tomography (X-CT) images of 3D printed objects were used. Guidelines for statistically sound sampling were also developed. The results show the extent to which different metrics are sensitivity to different types of flaws and offer ways of comparing the effect of processing conditions on print fidelity.